Grinding machine



June 24, 1941. H. P. TRCIEHNDLY ET AL GRINDING MACHINE Filed Feb. 23.1939

12 Sheets-Sheet 1 Unven l'ors Harry P fl'oelzdly Auws B. Ru us 951 Joseph Bolzuv- H. P. TROENDLY ET AL June 24, 1941 GRINDING MACHINE Filed Feb. 23, 1939 I2 Sheets-Sheet 2' U 5 PB 3 m3 Hm o June 24, 1941. H. P. TROENDLY ETAL GRINDING MACHINE 12 Sheets-Sheet 3 Filed Feb. 25, 1939 Unverd'or Hal-1 9R 7-oeadly Anws B. Puluseg Joseph Bohll June 24, 1941.

H. P. TROENDLY ETAL 2,246,869

GRINDING MACHINE Fil ed Feb. 23, 1939 12 Sheets-Sheet 4 I F 9 N u g I Harry P Troelldg AHlOS B. Runzsey Jos Iv Bola", a 311 June 24, 1941. TRQENDLY AL 2,246,869

GRINDING MACHINE Filed Feb. 23, 1939 12 Sheets-Sheet 5 Unvenl'ors Hal/y I 71"oe1zd'ly Amos B.Ruiuseg I Joseph, BO/tllb.

June 24, 1941. p TROENDLY AL 2,246,869

GRINDING MACHINE Filed Feb. 25, 1939 1-2 Sheets-Sheet 6,

ma q 2; a P B. w; a? A W W June 24, 1941. H. P. TROENDLY ET AL 2,246,869

GRINDING- MACHINE File d Feb. 23, 1939 IZ-Sheets-Sheet 7 nvent'ors Harry R Hoe/wa Autos B. Puuzseg \fosep/L BO/UIL.

June 1941- H. P. TROENDLY ET AL 2,246,869

GRINDING MACHINE Filed Feb. 23, 1959 12 Sheets-Sheet 8 nven't'o r5 Harry R floeadlg A01 5 B. Runzsey Joseph B o/um.

June 24, 1941. H. P. TROENDLY ETAL GRINDING MACHINE Filed Feb. 23, 1959 12 Sheets-Sheet 9 Unvenl'ors Harry R floelzdly Anws BJfiunsey Joseph Bo/LHL.

June 24, 1941. H. P. TROENDLY ETAL 2,245,869.

GRINDING MACHINE 1 2 Sheets-Sheet 10 Filed Feb. 23, 1939 mwv a,

. r p m3 H m June 24, 1941. H. P. TROENDLY ET AL.

GRINDING MACHINE l2 Sheets-Sheet 11 Filed. Feb. 25, 1930 3' n v e nj'ors Harry I? Troeudly Amps B-Punzsey M Joseph Bo/uw.

June 24, 1941. H. P. TROENDLY ETAL GRINDING MACHINE 1'2 Sheets-Sheet 12 Filed Feb. 23, 1939 S'nvent'Ol'S Harry P. Troendlg Amos B. Ramsey Joseph Boluzv.

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M EMDWN NQ Q4042: Q 95 n m E02- Patented June 24, 1941 GRINDING MACHINE Harry P. Troendly, Chicago, Ill., and Amos B. Ramsey and Joseph Bohm, Beloit, Wis; said Ramsey and said Bohm assignors to Gardner Machine Company, South Beloit, 111., a corporation of Illinois, and said Troendly assignor to Associated Spring Corporation, Bristol, a corporation of Delaware Conm,

, Application February 23, 1939, Serial No. 258,024

' 40 Claims.

This invention relates, generally, to grinding machines and, more particularly, to that class of grinding machines in which the work is given a (6) A- single hydraulic and electric control system for the entire machine which will cause the operation of the parts in their proper sereciprocating motion between opposed rotating grinding wheels. The invention provides a machine which is particularly' intended for the' bers into which the springs are loaded and which are adapted to be locked to a work-carrying table for reciprocation between the grinding wheels.

(2) Work loading, indexing and unloading mechanism, characterized by frame members which carry the work-carrying paddles and which are rotatable about a horizontal axis to move the paddles from a, loading position, in which unground springs are loaded therein, to a position from which the paddles are moved onto the reciprocable, work-carrying table and are removed therefrom after the grinding operation is completed, after which the paddle of ground springs is moved to a position where the springs are dumped therefrom. This general means includes indexing mechanism which causes the movement of the frames to proper positions and, further, efiects the locking of the frames in such positions duringthe grinding operation. (3) Means operable to lock the work-carrying paddles to the work table, and which means are moved, at the completion of the grinding operation, to unlocked position to thereby permit removal of the paddle from the table.

(4) Means for moving the grinding heads toward each other, which means will be operable to give theheads an initial quick movement, followed by a graduated infeed to a finish grinding position, after which the heads will be retained in such position for a sparking-out period and will then be quickly withdrawn from the work.

(5) Means operable to reciprocate the workcarrying table during the grinding operation and to automatically bring this to a stop in unloading position when the grinding heads have completed their inward movement and' the sparking-out period has been completed.

quence and will prevent the operation of any part or mechanism until all other related parts are in proper position or condition of operation.

An important object of the invention is the provision of a grinding machine in which the articles to be ground, such as springs, aregiven such a movement with respect to the grinding wheels that all of such articles are caused to travel across the entire face of the wheels and are all therefore in contact with the abrasive grinding wheels for equal periods of time, whereby all of the articles being ground are sub ected to the grinding action of all of the various grinding areas of the wheels for equal periods of time, thus effecting a more uniform grinding action and also causing a more uniform wearing of the grinding surfaces.

A more particular object of the invention is the provision of novel means operated by the movement of the grinding heads toward and from each other for controlling the rate of movement of the heads.

A further particular object is the provision of cushioning means-between the grinding heads, whereby a more gradual and controlled movement of these parts is effected.

A further particular object is the provision of work loading, indexing and unloadi mechanism which is operable to .move the work carrying paddles about a horizontal axis in carrying them from charging position to leading position and then to unloading position.

A further particular object is the provision of novel means for mounting the work-carrying paddles on the work table, which mounting means are so constructed as to preclude any possibility of clogging thereof by material ground from without the indexing fixture, as shown on 2-2 of Fig. 1;

Fig. 3 is a plan view of the complete machine; Fig. 4 is an enlarged fragmentary tially in section, similar to Fig. 2;

Fig; 5 is an enlarged fragmentary view of the left-hand end of the machine illustrating the mechanism controlling the, movement of the' heads;

Fig. 6 is a plan section taken on the'line H ofFig. 5;

line a view, par-.

Fig.- 10 is an enlarged fragmentary view of the means for locking the paddles on the reciprocating table;

Fig. 11 is a vertical section of the locking mechanism taken on the line llll of Fig. 10; Fig. 12 is a fragmentary section taken on the line l2l2 of Fig. 11 and illustrating the rollers supporting the paddles on the reciprocating table, and the structure whereby the rollers are. kept free of grit;

Fig. 13 is a plan view illustrating the location and interconnection of the various hydraulic de-. vices; v

Fig. 14 is an end elevation of the wheel dressing device; I

Fig. 15 is a horizontal section taken on the line l5l5 of Fig. 14;

Fig. 16 is a horizontal section taken on'the line IG-IG of Fig. 14; and

Fig. 17 is a diagrammatic sketch illustrating the complete electric and hydraulic control circuits.

GENERAL STRUCTURE The grinding machine provided by the present and 3, each grinding wheel and its shaft, pulleys,

driving motor and supports and bearings form a unitary structure which is supported on V-type ways 9 which extend at right angles to the grinding face and parallel to the driving shaft of the grinding wheel. Each grinding assembly may, accordingly, bemoved along its V-type support toward or away from the other wheel by means which will be described fully hereinafter.

The grinding assemblies described are slidably mounted on a base III which also slidably supports an elongated horizontal work table II which extends beneath the grinding wheels at right angles to the axes thereof. This table is mounted for reciprocation at right angles to the axes of' the grinding wheels on V-type ways I! and means, to be described hereinafter, are provided for causing the reciprocation of the table and its proper. operation with respect to other parts of the machine. The work table II carries on its upper face an elongated, horizontally disposed track or support l3,- the upper, longitudinal edge of which is provided, along its length, with spaced, semi-circular depressions ll,

which are clearly illustrated in ms. 11 and 12, and within. each of which is rotatably- Journaled a roller l5, the periphery .of which extends above the upper edge of the track l3, thin providing'a' seriesof rollers along the upper edge of thetrack and along which and upon which the lower edge of a spring-carrying paddle I! may be moved and supported. Means, to be described hereinafter,

are provided for locking the paddle to the workcarrying table in order that the paddle and the springs carried thereby will be moved with the' table when thesame is reciprocated, to thereby effect the grinding of the springs carried by the paddle. I

The spring-carrying paddles l6 comprise rectangular plates having a large number of openings extending therethrough within which spring coils may be positionedthe thickness of the .plate being such that the ends of the coils extend beyond the opposite faces of the plate,

In order to protect the grinding wheels and work table, and also in order to enclose and restrict the dust and small particles of metal generated by the grinding operation, the wheelsare enclosed by a protective housing II which surrounds the wheels'on their outer and upperfaces and peripheries. This casing extends in general parallelism to the work table and is provided at the extremities thereof with entrance guides I! which align the springs in the work-carrying paddle 16 with the grinding faces of the abrasive wheels and which act to maintain the paddle carried by the work table in proper position and alignment. V

Wheel dressing mechanism, illustrated in Figs. 14, 15 and 16 of the drawings, is provided for truing and dressing the grinding wheels and will be described more fully hereinafter.

In order to effect the charging of the spring- ,carrying paddles, the movement of these to a position from which the paddles may be loaded onto the work table, and, after the completion of the grinding operation, the subsequent movement of the paddle to a position where the ground springs may be dumped, an indexing mechanism whichis shown generally in Figs. 1 and 3 and isillustrated more particularly in Figs. 7, 8 and 9 provided.- Associated with this indexing means is an hydraulically operated mechanism for moving the charged paddle onto the reciprocable work table II and, after the completion of the grinding operation, moving the paddle from the work table into the indexing mechanism which, as heretofore described, then moves it to a dumping position.

All of the various parts of the machine are operated and controlled by aunitary hydraulic and electric control system, which is so operable that none of,the various parts and mechanisms may be operated until all other parts and mechanisms are in proper position or operative condition. This general control system will be described more fully hereinafter.

In order to more clearly describe the various parts and operative mechanisms which combine and cooperate to make up the machine illustrated, and in order to more clearly disclose the various features of the invention such various parts and mechanisms will be separately described.

' Indexing mechanism:

Means are provided by the invention for moving the spring-carrying paddles to charging,

loading and dumping positions, this means being removed from the mechanism which actually 4 effects the grinding operation but being accessory thereto and forming a part thereofinasmuch as the hydraulic and electric control for the indexing mechanism is interlocked and operable with the control means for the grinding mechanism. This indexing means is generally illustrated in Figs. 1 and 3, and is more particularly disclosed iii-Figs. 7, 8 and 9, while the control mans therefor and the interconnection of such control means with the control for other parts of the grinding machine is illustrated in Fig. 1'7.

Referring to the aforesaid figuresof the drawings, it will be seen that the indexing mechanism comprises a supporting base 20, which is spaced from the base ll) of the grinding machine, and which is provided with bearings 2| which rotatably support a horizontal shaft 22 which is aligned with and is approximately at the level of the upper surface of the track or support on the work table II. Mounted on the end of this Means are provided by, the invention for facilitating the charging and dumping of the paddles.

Such means are clearly disclosed in-Figs. 8 and 9 and comprise chutes 28, one of which is provided for each of the fourframes 23, and each of which comprises a bottom 21 which extends radially of theshaft 22 and two side walls 28 which extend at right angles to the bottom member. Each of these chutes is pivoted to the central support 24 adjacent one of the frames 23 with its side wall members extending in such a direction as to prober 29 which is coextensive with the bottom 21 and is spaced therefrom by suitable supporting shaft adjacent the work table II are four frames 23 which are spaced at 90 intervals about the shaft and are rigidly attached thereto and extend radially therefrom. Each of these frames is formed of structural members carried by a central support 24 which surrounds and is mounted on the shaft 22 and the structural members of each frame form merely a skeleton, open structure which is of small thickness relatively to its radial and longitudinal dimensions.

Each frame is adapted to removably receive a spring-carrying paddle which, when disposed withinthe frame, extends longitudinally of the shaft 22. The radially separated walls of each frame are therefore each provided with a centrally-located row of spaced rollers 25 which may be mounted in recesses in the manner described in connection with the rollers carried by the work table andillustrated in Fig. 12. These spaced rows of rollers are adapted to receive and support the upper and lower edges of a paddle l6 within which springs may be loaded, asiHustrated in Fig. 9. Each frame. is so constructed that a paddle may be moved into it longitudinally of the shaft 22 and, when so-positioned within the frame, will be held in position therein by the rows of rollers 25. I

Inasmuch as the four frames extend at 90 intervals from the shaft 22, the two horizontal positions into which the frame may be moved are employed as charging and dumping stations, while the vertical, upward position is utilized as a loading position, in which'the frame is so positioned that the paddle carried thereby may be moved along the rollers 25 directly qnto the rollers l5 of support |3 on the work table II. Thus,

in Fig. 9, the frame 23ais shown in loading position, having-a paddle therein which is in horizontal position in order that springs may be loaded therein. The frame 23b, which is' in the vertical, upward position, has a fully charged paddle of springs therein which is in position to be moved onto the work table. The frame 230, which has just been rotated from the vertical upward position in which it received a paddle of finished springs from the grinding machine, is now in a horizontal position in which the springs have been dumped from the paddle carried thereby. The frame 23d is at an inactive station and will next be rotated to the charging means.

The chutes described are adapted, in one of their positions, to underlie a frame 23c which is at the dumping station and to provide a chute for guiding the springs dumped therefrom into a receptacle 3D. In another position, the separate bottom wall 29 of each chute is adapted to underlie a frame 23a, which is at the charging position, in order to provide a support for the springs which are being charged into the paddle carried by such frame, to thereby hold such springs in the paddle.

Means are provided by the invention for moving the chutes to the various positions required in performing the functions described. Such means, which are disclosed in Fig. 9, comprise a cam member 3| which is rigidly supported adjacent the shaft 22 but does not move therewith. The periphery of this cam is engaged by rollers 32 which are carried atthe outer extremities of arms 33, the other ends of which are rigidly attached to the chutes 26 adjacent the pivotal connections thereof to the central support .24. Associated with the pivotal connectionv between each frame and the central support are resilient means, such as springs 34 whichconstantly urge moved, by the engagement of its arm 33 and roller 32 with the cam 3|, into such a position that it is inclined below the frame 230 and is so positioned that its lower, open end is adjacent the receptacle 30, whereby the ground springs in the frame 230 fall into the chute and are led to the receptacle.

As the indexing fixture revolves, the chute, be-

ing carried therewith, is moved, by the springs acting on its pivotal connection to the central support 24,. to a position in which the separate bottom member 29 thereof closely underlies the frame 230. which is in the loading position, the

station inorder to receive new unground' springs in the paddle carried thereby. It is contemplated that a paddle, when once placed in, a frame, will normally remain with that frame until its removal is required.

shape of the cam 3| being such as to permit this positioning of the chute. In this position the separate bottom member '29 supports the springs tziging loaded into the paddle carried by the frame Means are provided by the invention for rotating the shaft 22 through the increments required, as hereinbefore described, stopping the shaft at the proper points, locking it at such points during the grinding operation and releasing it for a further movement when the grinding operation is completed. Such means are disclosed in Figs. '1, 8 and 1'7 and comprise two disks 46, 4|, both of which are keyed to the shaft 22 at the extremity thereof removed from the frames 23. The innermost disk 46 .is the driving disk and the periphery thereof is provided with teeth which are engaged by a gear 42 which is carried by the shaft of a fluid motor 43 the control means for which determines the rotary 'movement of the shaft 22. The disk 4| is the control diskand has formed in its periphery four slots or apertures 44 which are spaced apart at 90 intervals and which are adapted to receive the end of a locking plunger or index pin 45, the other end of which is attached to a piston 46 which is slidably received in a cylinder 41 and is constantly urged by a spring 46, disposed within the cylinder, toward thedisk 4|,

The periphery of the control disk 4| is also provided with four, equally spaced sets of control members, each set including a valve control abutment 49 and a switch control abutment 50, these being so positioned that the abutment 49 leads the abutment 50 as the disk rotates in a clockwise direction as viewed from the end ofthe shaft.

By reference to Fig. 17 of the drawings, it will be seen that the motor 43 is in a hydraulic circuit having its originat the reservoir and leading through pump 52, double solenoid valve 53, conduit 54 to the cylinder 41, conduit 55'to motor 43, valve 56 andthence back to reservoir 5|. The solenoid valve 53a is operable, when energized, to permit fluid to pass from the reservoil' to conduit 54,'and is energized by depressing switch 60; completing a circuit through solenoid 53a and limit switch 11 which provides a safety interlock with the work loading and unloading means. the cylinder 41 below the innermost locking position of thepiston 46, while the conduit 55 is connected to the cylinder in such a way that when the piston 46 therein is in its normal, spring-pressed, locking position this conduit is blanked and cut oil from communication with the cylinder or with conduit 54.. The valve 56,

is normally maintained in a position permitting free passage of the fluid output of the motor 43' therethrough, but upon engagement of the stern of the valve by one of the valve abutment members 49 carried by the control disk, the passage through the valve is restricted, thereby reducing the speed of rotation of the motor and, consequently, the shaft 22. A normally closed switch 51 is arranged adjacent the periphery of the disk 4| and 'is connected between thesource of power and solenoid valve 53a, and acts with the interlock switch 11 to normally complete the circuit including solenoid 53a. Switch 51 is instantaneously moved to open position, deenergizing solenoid 53a when engaged by one of the abutments 50" as the shaft 22 reaches a position in which the frames carried thereby are opposite their respective stations.

In the operation of the indexing mechanism from a stationary, locked condition, thecontrol switch 66 is operated to close the circuit through solenoid 53a, thereby operating the valve 63 to cause fluid to be supplied by pump 52'through the valve and conduit 54 to the inner side of piston 46, thereby moving the piston against the force of spring 46, releasing the index pin 45 from locking engagement with disk 4| and putting-the conduit 55 in communication with conduit 54 .through cylinder-41; Fluid will therefore flow to motor 43, operating the same and causing the shaft 22 and disks 46 and 4| to rotate. This rotation will continue until one of the valve abutment members 46 engages the stem of valve 66, whereupon the valve 66 will be operated to restrict the output of motor 43, thus retarding the speed of the motor and of the-indexing mechanism. When one of the apertures 44 in the disk 4| is directly opposite the locking pin 46, one of the switch abutment members 66 will engage the switch 61, operating it to open position and there;

by deenergizing the solenoid 63a and moving the valve 63 to position. to completely unload the motor and stop the rotation thereof. This action will also relieve the pressure from the lower side of piston 46, thereby permitting the spring 46 to move the pin 45 into locking engagement with the adjacent aperture 44.

It will be seen that the shaft 22 and disks 46, 4|

,may be rotated through only 90, due to the spacing of the valve and the switchactuators 46, 66.

through 90 will, of course, effect the movement of the frames 23 through equal intervals, thus moving each frame to the next succeeding static while the movement of the chutes 26 with respect to the cam 2| will cause the chutes to assume the predetermined positions heretofore described. 1

The operating means for the indexing mechanism is interlocked with the operating means for other mechanisms and parts of the entire machine, whereby the indexing mechanism may be The conduit 54 is connected to position,

operated only when other of the machine are in proper position and operating condition. This interlocking means will be described hereinafter in connection with the description of the general hydraulic and electric control for the machine.- l

Work loading and unloading means Means are provided by the invention for moving a loaded paddle from the indexing mechanism onto the work table of the grinder, and for removingthe paddle from the grinder into the frame of the indexing mechanism when the grinding operation is completed.

Such means are particularly illustrated in Figs. 7 anal-'7, and comprise an elongated cylinder 66 which is mounted above the shaft 22-01 the indexing mechanism and is so positioned that it is aligned with the paddle carried by the frame which is inthe vertical, upwardly-extending positlon, i. e., the position of the frame 231) inFig. 9. A piston having a piston rod 61 is slidably disposed within the cylinder 65, and the outer end of this rod,.which is adjacent the paddle and frame assembly, is provided with an enlarged head 66 to which there is pivotally connected a right-angled latch device having a horizontal, forwardly-extending latch portion- 66, a vertical, upwardly-extending arm 16 and a vertical, downwardly-extending arm 1| which, when the piston is in its retracted position engagesan abutment 12 which rotates the latch lever in a counterclockwise direction and moves the latch portion an inoperative position. A

66 upwardly into cross-center spring 13 is connected between the parts and mechanisms latch portion 69 and the head 66 and extends across the pivotal support of the lever. The upper portion of the head 66 has connected thereto the forward end of'an elongated rod 14 which is received in a guide "and has the purpose of' preventing any turning of the piston rod and head about their axes. The lower portion of the head 66, when the piston is in its most retracted engages two switch elements 16 and 11 paddle. closed or energized position during the entire and operates these for a purpose'whioh will set forth hereinafter. As illustrated in Figs. 3,? and 8, the latch portion 69 'is constantly aligned with the latch'poridon I9 which is formed on the end of the paddle received in the frame whiclris in the vertically upward position. A conduit .19 is connected to the head end of the cylinder 96 and a second conduit 89 isconnected to the rod end of the cylinder. As illustrated in Fig. 17, the flow of fluid through these two conduits is controlled by the four-way solenoid valve 9| and the master control valve 53.

The work loading and unloading cylinder is normally unloaded, and the piston 66 in the cylinder is normally in retracted or unloading position, the fluid under pressure being Jay-passed through valves 53 and 9|. In this retracted position the abutment I2 engages the arm 'IIof the' latch lever, causing the spring 13 to hold the latch portion thereof in raised, inoperative position. When a paddle of unground springs has I been rotated to loadingposition and it is desired to move the paddle onto the work table, the solenoid 9Ia of four-way valve 8| and solenoid 53b,

of .valve 53 are energized through interlock limit switch 393 by operation of switch 82, causing fluid under pressure from the pump to be directed to the rod end of locking cylinder 91, moving the lock -pi'n downwardly. -As' the pin 92 moves downwardly, fluid is by-passed'through the lower port in cylinder and through conduit I92 and valve M to the head end of the loading cylinder 65. The piston rod is accordingly moved toward the paddle, the arm II of the latch lever engaging the portion I8 of the paddle, thereby moving the latch 69 into operative position, thereby causing the latch to engage the latch portion of the paddle and move the paddlefrom the frame onto the work table of the grinding machine, the paddle moving on the series of rollers I5 and 25. When the piston has moved the paddle to its proper position on the'work table the upwardly-extend-' ing portion 19 of the latch lever engages an abutment, causing the lever to move about its pivot in such a way as to release the latch 69-from the Theswitch 92, which has been held in loading movement of the piston is now released or moved to deenergiaing position, thus causing the solenoid valve 8I to return to a position in which fluid under pressure is removed from the head end of the cylinder 65 through conduit 19 and is supplied to therod end of the cylinder through conduit 89, thus moving the piston rod, the head 68 and the latch means to retracted position.

When the grinding operation is completed and it is desired to remove the paddle from the grinding machine to the indexing fixture the switch 82 is again operated to cause'the piston 66, rod 91 and head 68 to move outwardly until the latch 69 engages the paddle, at which time the switch 82 is moved to deenergizing position, thus causing the piston to move to retracted position, carrying the paddle out of the grinding machine into the frame 23b of the indexing mechanism. When the piston reaches its fully retracted position, at which time the paddle will be in its proper position in the frame 23?), the

, downwardly-extending lever arm II will engage the abutment I2, thus releasing the latch from the paddle and permitting the paddle and frame to be turned by the indexing mechanism to dumping position, in the manner described hereinbefore.

The operating means for the-work loading and unloading mechanism is interlocked with the operating means for other mechanisms of the entire machine, whereby the loading and unloading mechanism may be operated only when other parts and mechanisms oi the machine are in proper position and operating condition. This interlocking means will be described hereinafter in connection with the description of the general hydraulic and electric control for die machine.

Work locking mew ts Means are provided by the invention for looking the spring-carrying paddle to the work table after it has beenmoved thereon by the work loading and unloading means heretofore described. Such lockingmeans are disclosed in Figs. 1, 10, 11 and 1'7 of the drawings. Referring particularly to Figs. 10 and 11, it will be seen that there is provided at the loading end of the work table II, 1. e., the end which is adjacent the indexing fixture, a U-shapedbracket 99 within which is received for vertical movement the enlarged end M of a vertically-arranged locking pin 92, which extends above the upper surface of the work table and which, intermediate its ends, is slidably received in a vertical guide 93 formed on the end of the track I3 of the work table. The locking pin is normally urged upwardly against a stop 94 by a spring 95 located in the bracket 99 and in this upward or operative position the upperend of the pin is adapted to enter a notch or aperture 99 in the lower face of a paddle I6 which is operatively positioned on the work table.

Means are provided for movingthe locking pin to its lowered or inoperative position in order to release a paddle which is on the work table or in order to permit a paddle to be moved onto or off of the work table. Such means comprise a vertically-disposed cylinder v9'! which is carried by the base or frame I9 of the machine and within which is arranged for vertical movement a piston 98 having an upwardly extending rod 99. To the upper end of the rod, 99 is connected a horizontal plate member I99, one side of which is bifurcated to receive the reduced central part of the enlarged end 9| of the locking pin, such end part 9| being formed at its upper and lower ends w h enlarged rings,'between which there isa reduced portion which is engaged, as aforesaid, by the bifurcated portion of the plate I99.

The upper surface of the piston 99 is provided with an abutment which prevents the piston from moving entirely to the upper end-wall of the cylinder 91, and the'space thus providedin-the cylinder above th upper limit of movement of the piston is connected by a conduit I9I to the four-way double solenoid valve 53 where its connection to the reservoir 5| .and other parts is controlled. Between its ends, and aboye the lowermost position to which the piston may bework locking means, fluid under pressure is out on from conduits IM and I92, and the spring 95 maintains the spool 9| and locking pin 92, in their 'uppermost positions. If it is desired to move a loaded paddle onto or off of the work table, the

locking pinmust first be lowered, and this is effected by operation of solenoid 33b of four-way valve 53 andsolenoid 3 Ia of four-way valve through interlock switch 303, causing fluid under pressure to be supplied by the pump 52 through conduit IOI to the upper end 01' the cylinder, thus forcing the piston 98' andpiston rod 93 downwardly and, through the connection be;- tween the bifurcated plate I00 and the enlarged end 9| oi the locking pin, also moving the locking pin downwardly so that its upper end is below theupper surface of the work table. The springcarrying paddle may now be moved onto the work table and into such a position that the aperture 36 in the lower face thereof is directly .above the locking pin 92. The movement of the work table away from its loading position causes the-spool member 9| tomove out of engagement with the bifurcated member I00, thereby causing the spring 95 tomove the pin 92 into locking engagement with the slot 96 in the paddle IS.

The operation of the work locking means is interlocked with the operation of other parts and mechanisms of the entire machine, whereby the work locking mechanism may be operated only when other parts and mechanisms of the machine are in proper position and operating condition.

This interlocking means will be described hereinafter in connection with the description of the general hydraulic and electric control for the entire machine.

Work table reciprocating means Means are provided by the invention for reciprocating the work table in order to cause a loaded paddle thereon to be moved past the 'grinding wheels in order to effect the-grinding of thesprings carried by the paddle. Such means are illustrated in Figs. 1, 11 and 17 of the drawin'gs and comprise a horizontally disposed cylinder IIO which is arranged below the work table and with its longitudinal length parallel to the direction of motion oi? the table. A piston I II having a rod II2 attached thereto is slidably disposed within the cylinder and the outer end of the piston rod is connected by a rigid connecting means II3 to the lower face of the work table. It is a primary featured the present invention that all of the springs carried by the work table are moved thereby over the entire faces of-the grinding wheels and, accordingly, the cylinder H0 and the piston rod I I2 are made of sufllcient length to provide the long stroke so required.

The forward and rearwardends of the cylinder IIO are connected, respectively, to a three-way pilot valve II4 by conduits H5, H6, such valve being also connected, by a conduit 1, to a reservoir I I8 and, by a conduit I I9, to ,a fluid I control device I20, the same being also con'-' nected to the reservoir IIB by a conduit I2I. Pilot fluid conduits I22 and I23 also connect the valve "4 to a double-solenoid, four-way control valve I24, one solenoid of which is controlled by a switch I25. It will be apparent that alternate introduction and release of fluid under pressure to and from the opposite ends of the cylinder IIO will cause the piston III and rod I I2 to reciprocate, thereby moving the work table back and forth, whereby the work is moved across the grinding heads. The control of the operatconnec cylinder H0, and such means comprise a rod I30 which is attached to or movable with the piston II2. This rod carries two spaced abutment mtgrnbers. I3I, I32, one of which is pivotally to the rod in such a manner that it wil1'swing only one direction, while the other is so mounted at it will swing only in the opposite direction. A pivoted switch device I33, which is connected to a source of power in a manner to be described hereinafter, has a portion arranged in the path of movement of these two abutments and has a contact portion which is adapted to be moved into engagement with either of two spaced contacts I34, I35. The rod I30 also carries a third abutment I36, and arranged in the path of movement of this abutment is a pivoted switch member I31 which is normally held by a spring in engagement with a contact I38 but is moved, when engaged by abutment I36 out of engagement therewith. Contact I 34 is connected to one terminal of solenoid I24b through lead 33I, while contact I35 is connected to one terminal of solenoid I24a through the two switch contacts I 31, I38 and lead "I, whereby current will be supplied to one or the other of the solenoids when the connected switch contact is engaged by movable contact I33.

The reciprocating movement of the rod I30 and abutments I3I and I32 causes the operation of the switch I33 to control the alternate supply of fluid to the opposite ends of the cylinder IIO, it being noted that each of the abutments I3I, I32 will operate the switch I33 in one direction of movement of the rod I30. The circuits controlled by the switches I33 and I31, the control of the hydraulic circuits which operate the piston I II and'the interlocking of these electrical and hydraulic circuits with the control means for other parts and mechanisms of the machine will be described fully hereinafter in connection with the description of the general hydraulic and electric control for the entire machine.

Grinding head feeding means bemoved toward each other atcontrolled speeds,

to positions which will effect the proper grinding,

and must then be moved apart. In order to effect the proper movement 01' the grinding heads, means are provided by the invention which are .eflective to (1) movethe heads toward each other at an initial rapid rate which takes up quickly the space between the normal, retracted positions of the heads and the unground work;

(2) move the heads further toward each other at addition, means.are provided for permitting a so-called jog cycle, which is used by the operator to touchup the work, and which causes a disposed in a cylinder I64.

rapid movement of the heads toward each other to a predetermined point, a dwell at this point, and thereafter a rapid retraction of the heads. Such head feeding means are illustrated in Figs. 2 to 6 and 17 of the drawings and reference will be had thereto.

As stated hereinbefore, the grinding heads, each of which includes a grinding wheel and driving means therefor, are mounted on supports which are, in turn, mounted on aligned V-type ways extending at right angles to the opposed, parallel faces of the grinding wheels and on which the heads may be moved toward and away from each-other. As illustrated in Fig. 2, the movable grinding assembly including the grinding wheel I has formed on the lower portion thereof a downwardly-facing rack bar I50, while the assembly including the grinding wheel 2 has rigidly attached to the lower portion thereof an elongated bar II which extends below the grinding wheels and terminates below the rack I50 in an upwardly-facing rack bar A pinion I53 is disposed between the two racks and has teeth which mesh with both of them. The pinion I53 is keyed to a shaft I54 which "is rotatably mounted in the frame portion of the machine, as illustrated in Fig. 6, and on this shaft there is also keyed a second pinion gear I55, .the teeth of which mesh with the teeth of a gear I56 which is keyed to a shaft I51. The

ratio of the gears I55 and I56 is made such that the grinding heads, which are moved by gear I55 are caused to move a short distance while the operating piston, which is connected to gear I56,

-moves a much greater distance, thus providing a better control of the infeed of the heads. The shaft I51 is journaled in the machine frame and has keyed thereto one end of a crank arm I58 which extends downwardly from the shaft I51 and, at its lower end, is bifurcated to receive a pin I59 which extends laterally from av block I60 which is supported by rollers'I6l in such a manner that it may move at right angles to the shaft I51.

The block I60 is adapted and intended to be moved in either direction at right angles to the shaft I51 on the rollers I6I and, to effect such movement, the block is provided with a passage which extends therethrough in the direction of the intended movement and through which freely passes a piston rod I62, the one extremity v of which is connected to a piston I63 which is The opposite end of the piston rod extends through and is threaded into a sleeve I65 which slides in a bracket I66 which is bolted to the machine. Sleeve I65 has an enlarged head at one end and locknuts at the external end which may be adjusted so that-the gap between them and the face of sleeve I65 is slightly greater than the ratio of movement of the piston I63 to the infeed travel of the heads. The sleeve I 65 may be adjusted on the piston rod by means of a handwheel I61. Only a portion of the stroke of operating piston I63 is .used, and the adjustable nuts prevent undue over-travelin moving the heads together, the

head of sleeve I acting as a stop in the opposite direction. The adjustment of the sleeve on the piston rod regulates the possible opening movement of the heads but does not affect the gap between the nuts and the face of the sleeve,-

the piston rod on opposite sides of the block and compression springs I10, "I are respectively disposed. between these abutments and the block, whereby movement of the rod in either direction will cause a corresponding movement of the block.

As illustrated in Fig. 17, the head end of the cylinder I64 is connected, by conduit I12, to' a four-way solenoid valve I13, whilethe rod end of the cylinder is connected to valve I13 through conduits I15 and I16 and a valve I14. It will be apparent that movement of piston rod I62, caused by\the admission of fluid under pressure to the cylihder I64 at one or the other side of the piston I63; will cause a corresponding movement of the block I60 on the rollers H, which movement will be transmitted through the pin I59 to the crank I58, causing a turning move-' ment thereofand effecting a corresponding rotation of the shaft I51. Such rotation of the shaft I51 will be transmitted through gearing I 56 and, I55 to shaft I 54, thereby rotating the pinion gear I53. 'The rotation of the pinion gear I53, which meshes with the two racks I50, I52 will cause these racks to move in opposite directions, and such movement-will be transmitted to 'the two grinding heads which are, respectively, connected to the racks. The grinding heads are thus caused to move toward or away from eachother by equal amounts and in accordance with the pressure applied to the piston I63. The resilient connection between the piston rod I62 and the block I60 will provide a cushioning effect between the prime mover, i. e. the'cylinder I64 and piston I63, andthe gearing which causes the opposite movement of the heads. This cushioning effect, will prevent the transmission of quick movements or shocks to the gearing and the grinding heads and will, therefore, cause an even and gradual movement of the grinding heads under all conditions.

Means are provided for. controlling the rate of feed of fluid under pressure to the opposite ends of the cylinder I64 in orderto effect the proper operation of the grinding heads in the manner hereinbefore set forth. Such means are illustrated in Fig. 17 and comprise a four-way, double solenoid valve I which is supplied, through conduit I8I, with fluid under pressure by a pump I19, the inlet side of which is connected to reservoir H8. The solenoids I80a and Nb of valve I80 are adapted, respectively, to

control the supply of fluid pressure to two out-' also connected to valve" I13 through a control device I-which is adapted to restrict or enlarge the flow of 'fluid through conduit I83 by the movement of a control arm I86. The solenoid I 801:, when energized, is operable to move the valve I80 to a position in which fluid under pressure flows from pump I19 through conduit I8I, valve I80, conduit I83, control device I85,

- pipe I82, valve .113 and conduit I12 to the head end of cylinder I64, thereby moving the piston-I63 and causing the grinding heads to be moved toward each other and toward the work. Solenoid I801). when energized, causes valve I 80 to move to a position in which fluid under pres+ sure flows from reservoir H8 and pump I19, through conduit I8I, valve I80, conduit I84, valve I13 and conduits I 16 and I15 to the rod end of the cylinder I64, thereby causing the piston I64 to move outwardly to move the grinding heads apart, it being noted that valve I13 is normally positioned to permit the described flow of fluid. The condition of the fluid control fluid through conduits I83, I82 and I12 andthus determines the rate of infeed movements of the piston I68 and, consequently, the rate of movement of the grinding heads toward each other. L

Means are provided for controlling the -position of the operating arm I86 of the fluid control device I85 in accordance with the position of the piston I69 and, therefore, in accordance with the position of the grinding heads, thus controlling the rate of inward movement of the heads in accordance with thepositions thereof with respect to each other and with respect to the work. Such means are illustrated diagrammatically in Fig. 17 of t e drawings and, more particularly, in Figs. 4, and 6 thereof.

Referring particularly to these figures, it will be seen that the rack I52 has connected there? to and extending exteriorly of the machine base,

a rod I96, the outer end of which is threaded to receive a handwheel I18 which may be operated to adjust the position of the rack I52 and the connected gearing. Surrounding the outer portion of the shaft I96, and being concentric by it moves therewith and with respect to shaft I96 and collar I9I. A shaft I93 is journaled in the housing I 11 and has connected to one end thereof a crank arm I92 which, at its free end is provided'with a pln' which is received within th groove in the collar I9I. A beveled gear 'I94 is connectedto the other end of shaft I93 and meshes with a beveled gear I95 which is carried at one end of a shaft I96 which is Journaled in the'housing I11. A disk I91 is slidably keyed'to shaft I96 and a removable cam surface I98 is attached to the periphery of this disk, and engages one end of a slidable follower I99, the other end of which is in engagement with an abutment carried by the pivoted control arm A spring '266 urges the control am into engagement with the end of the follower I99 and in such a direction as to restrict the flow of, fluid' between conduits I82 and I89. The parts are'so arranged and operable that movement-ef the grinding heads toward each other causes movement of the cam surface I98 in such a way that the follower I99 is lowered and the control arm I86 is accordingly caused to move in such a way as to restrict the flow of fluid to the head end of the head feeding cylinder, while movement of the grinding heads away from each other causes fluid to be by-passed through a check valve in valve I85 which permits full flow regardless of the position of cam I98, thereby permitting fluid to flow without restriction to the rod end of the head feeding cylinder.

Means are provided by the invention for controlling the flow of operating fluid to the ends comprise, broadly, a circuit for operating the solenoid I86a to cause operating 'fluid to be admitted to the head end of cylinder I64 to move the grinding. heads together, and a second circuit which is operable upon completion of the inward travel of the heads to causev the solenoid I86a to be de-energized and, after a suitable period of time controlled by a time-delay relay, to cause the solenoid I86b to be energized tosupply operating'fluld to the rod end a of the cylinder I64 to move the grinding heads contact 269,. The operatingarm 261 is connected to the ource of power through lead 356 and interlock I69, while the contact 269 is connected to a time-delay relay device in such a way that when this contact is engaged by the contact 261 and current is supplied thereto the relay is operated to. supply currentto solenoid l86a. Contact.

261 is normally in engagement with contact 269 and is moved out of engagement therewith only when'the control arm I86 is moved to the limit of its possible movement in a counter-clockwise direction by movementof cam I98 as the'grinding heads are moved together. The contacts 261 and 269 are again moved into engagement when the of cylinder I64 in such a manner that the movement of the grindi'ng'heads will be controlled in the desired manner. As stated hereinbefore,

the four-way valve I86 is provided forthis purheads are moved apart, by means of the rotation of control arm I86 by cam I98. I

By reference to Fig. 6 it will be seen that a microswitch 262 is positioned between the collar I9I and parts of the housing' I11. The contact elements of this switch are normally separated but are adapted to be brought into engagement when the collar I9I engages the housing I11 t the end of the movement of the heads towar each other. One contactof this switch is connected to the source of power while the other is connected to the aforesaid time-delay relay device in such a way as to operate the same to cause energization of solenoid I 86b after a suitable dwell, thereby causing the grinding heads to be moved apart.

It will be seen that the operation of head feeding control, means consists in energization of the solenoid I86a to cause operating fluid to be supplied to the head end of cylinder I64, moving the heads toward each other. As this movement continues, the rod I96and the housing I11 will be movedin opposite directions, being respectively mounted on thetwo grinding heads, and the crank I 92, shaft I93, gear I94, shaft I96 and disk I91 will therefore be rotated, causing the cam I 98 to. move the follower I99. The spring 266 will accordingly cause control arm I86 to rotate,

adjusting the valve which is 'controlled'thereby to restrict the flow of fluid through control device I and therefore to the head end of cylinder I64. The movement of the grinding heads toward each other will therefore be retarded and the grinding wheels will advance against the work at a controlled rat, I

When the heads have reached the predetermined limit of their inward movement, a solid stop will be engaged and the micro'switch 262.

will be operated, energizing the time-delay relay which; after a suitable period of time, operates to connect the solenoid I96b to the source of 

